It is known that the result of measuring electricity consumption of electricity users or the result of measuring the electricity generated by photovoltaic power generation is sent to a server for the purpose of electric energy management. Moreover, it is a known fact that large-scale energy management, on a larger scale than households or buildings, is performed via a network.
However, if there is an increase in the number of electric power devices that perform discharging or charging and that are connected to a network, it leads to an overload in the amount of information that is communicated via the network. As a result, it becomes difficult to perform communication in an efficient manner.